71. The Palaeozoic era contains ____ time periods.
A. Six
B. Four
C. Five
D. Seven
72. The northern portion of the western coastal plain is called
A. Konkan plain
B. Malabar coast
C. Coromandel coast
D. None of the above
73. The ozone layer at high altitude contains
A. Atomic oxygen (O) and ordinary oxygen (O2)
B. Only ozone (O3)
C. Mixture of atomic oxygen (O), ordinary oxygen (O2) and Ozone (O3)
D. Only ordinary oxygen (O2)
74. The number of a topographic map is 47A/16/NW. Its scale must be
A. 1 : 250,000
B. 1 : 100,000
C. 1 : 50,000
D. 1 : 25,000
75. The right ascension is the equivalent of longitude on the celestial sphere, and it is given in the units of
A. Degrees
B. Time-hours, minutes and seconds
C. Only hours
D. Only seconds